The invention relates generally to cable management and, in particular, to a device for providing bend radius and microbending protection of cables entering, exiting, or contained within cable management and distribution systems.
The use of fiber optical cable is limited in modem applications by a minimum bend radius and, further, by the incidence of microbending. A fiber cable bent beyond the minimum bend radius typically suffers signal degradation. Microbending occurs, for example, when a cable is pulled tight across a sharp corner or edge and results in high attenuation of the signal and can degrade or interrupt signal transmission.
Fiber optic cable that is brought into a building for use in transmitting coded or modulated signals, such as telephone (voice), cable (video), or computers (data) signals, must be distributed throughout the building to each location that requires access to the information being transmitted. To facilitate that distribution, enclosures, racks, connect panels, and channel systems are typically utilized to house and manage the dispersal of the fiber.
FIG. 1 shows an example of a distribution enclosure 10. Distribution enclosure 10 allows cables to enter and exit the enclosure at openings 12. In many cases, as many as seventy-two fibers are distributed within a single enclosure and several of these enclosures are attached to a rack. In larger systems, a room full of these racks serves as a central hub from which thousands of fibers are distributed.
The multitude of fibers entering and exiting distribution enclosures and other cable management devices and the proximity of hardware equipment to such devices results in a high incidence of microbending. Any fiber entering or exiting an enclosure can be subject to microbending by being pulled tight across a sharp edge or pinched between two pieces of hard plastic or sheet metal. A fiber contained within a cable management device is susceptible to bend radius breaches and microbending about parts within the management device.
FIG. 2 depicts a cable retainer 20 common in the art for managing the distribution of fiber cables in a cabling system. Cable retainer 20 includes a first loop 22 disposed adjacent to a second loop 24, both for retaining layers of cable. The cable retainer further includes a quarter turn fastener 26 for securing cable retainer 20 to a cable distribution enclosure, rack, or other device of a cable management system. Cable retainer 20 may be used in combination with a plurality of cable retainers 20 to direct the path of cable. The cable retainer, however, does not protect a cable against exceeding minimum bend radius nor against the occurrence of microbending.
FIG. 3 shows a perspective view of a cable guide 30. Cable guide 30 includes a semi-cylindrical member 32, a first member 34, and a second member 36. First member 34 and second member 36 are disposed at either end of semi-cylindrical member 32 perpendicular to the longitudinal axis of said member 32. First member 34 contains slots 35 for mounting the cable guide device to various cable distribution and management equipment. Cable guide 30 further includes a plurality of flanges 38 disposed on the semi-cylindrical member parallel to first and second members 34 and 36.
Cable guide 30, however, is not designed to protect cables retained thereby against the hazards of minimum bend radius violations.
Additionally, cable guide 30 does not provide for expansion of a cable system. That is, once installed, a user is limited to the surface area of the cable guide. If a cable management system expands requiring a number of cables in excess of that which can be supported by installed cable guides, the guides must be disassembled, larger guides acquired, and then the larger guides installed.
Moreover, cable guide 30 requires specific mounting hardware and the use of tools to install the guide in a cable management system.
The inflexibility and limitations of cable guide 30 result in inconvenience and inefficiency to a user.
Accordingly, it is desired to have a device for providing bend radius and microbending protection of cables entering, exiting, or contained within cable management and distribution systems.
The above discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by a stackable bend radius guide of the present invention. The stackable bend radius guide is an effective cable management device for preventing deleterious effects associated with microbending and minimum bend radius violations of fiber optical cables.
In one embodiment of the present invention, the device uses an arcuate surface and a plurality of guide flanges to direct fiber cables so as to prevent microbending and minimum bend radius violations within a cable management system. The device includes both a quarter turn fastener and an opening for receiving quarter turn fasteners. In this way one bend radius guide may mate with a plurality of bend radius guides combining to provide a bend surface area required for a particular cabling application. The quarter turn fastener further allows for ease of installation and disassembly by requiring no tools and no mounting or attachment hardware.